Thorn Nomad MKII comments after 6000 km on dirt roads of American west

[il padrone]

I found the contrary to be the case. The mudguard and crud catcher both collect mud and then make it that much more difficult to clean the bike. The mudguard, in particular, can be a menance in heavy mud, since so much mud collects that the wheels won't turn...

No, I'm not talking about heavy, tyre-clogging mud, just the typical road dirt and grime that you get all over the bike when riding on wet roads, whether gravel or tarmac. This throws a lot of grime all over the bike if you don't have mudguards. With mudguards the bike stays much cleaner. Just my experience.

As for drenched shoes, that is of no concern for me while touring.

It starts to become a concern when the temperatures are dropping and you begin to lose feeling in your toes 

[Andybg]

I dont know if you can still get them but I remember in the late 80's there being a combined chain slap guard and "sharks fin" that was designed to clean this mud off the tyre thereby protecting the frame? Not sure if it was a good idea or not or if still available but is food for thought.

[keleher]

4. Chain wheel takes a beating when dragging the bike over boulders. I haven't noticed any damage to my chain wheel, and these Thorn chain wheel are from the high-quality 7075 alloy rather than cheapo aluminum, but they are still aluminum. Anyone broken their chainwheel teeth from banging on rocks? Anyone gone with the steel Surly chainwheel as a sturdier alternative?

Andy, I used a 50t surly chainring for a while, but it bent when I hit a boulder! Now I'm happily using a 48t Thorn.

[Danneaux]

I used a 50t surly chainring for a while, but it bent when I hit a boulder! Now I'm happily using a 48t Thorn.

Hi Pete!  I've had good luck protecting my chainring (and leg, from grease) through use of a crank-mounted bashguard. The one I am currently using is a Thorn, as here: http://www.sjscycles.co.uk/page/find/?name=thorn&page=1#filterkey=cat&cat=504&page=1 I'm using the 44T bashguard with my 40T chainring.

It uh, seems to be working. Though I didn't strike a rock, one struck me, having flipped off my front tire (and somehow past my mudflap -- how?!?  ) on a recent fast downhill on a very steep logging road in the Coast Range. It chipped the finish on the bash guard, then glanced lightly off the point where the right crack arm blends into the mounting spider. Good news? I found Toyota's Black Metallic TY 01566/204 is a dead-on match for Shimano's Deore HollowTech II "starry night" micro-metallic black crank paint.

Earlier, I used a BBG Bicycle Bash Guard (made in Portland, Oregon) on my Sherpa: http://www.bbgbashguard.com/Mountainbike.html , specifically this one.

My main reason for running a bash guard is to keep my right leg clean of greasy oil when touring (and, on Sherpa, to keep the razor-sharp profiled teeth on the outer chainring from tearing my calf when the chain was elsewhere). Let's look at this scientifically: The interior of a clean sleeping bag is the most effective known method for automatically removing chain oil from bare legs. Effectiveness positively correlates with purchase price and increases when applied in pitch dark and catalyzes in the cold, harsh light of dawn. Since one might slide into the bag on entry, removal action includes a bonus grease redeposit on fresh cycling jersey(s) on subsequent nights. Product includes a bonus language course at no extra cost.

Best,

Dan. (Bash guards prevent a host of ills...)

[Danneaux]

I remember in the late 80's there being a combined chain slap guard and "sharks fin" that was designed to clean this mud off the tyre thereby protecting the frame? Not sure if it was a good idea or not...

Good memory, Andy, and accurate, too!

That would have been Shimano's patented adhesive Sharkfin chainstay protector, shown properly installed in a later version using a securing zip-tie here: http://www.jensenjensen.com/img/xbike/1040_shark_fin.jpg

In truth, it didn't work so well as a mudscraper because it worked too well! All the mud it scraped was deposited directly on the innermost and middle chainrings, making things a bit worse for the installation.

They worked better as a means for preventing chains run on double-pivot rear mechs from getting pulled down into the chainstay-tire gap by tires with aggressive side-knobs. This problem was ultimately solved with greater clearances and increased spring tension in the rear mech. Shimano's new Shadow series of single-pivot mechs does an even better job.

For a truly horrendous picture of a mud-doused Rohloff that kept on going, see this example, owned by Martijn Raap in use on his recent tour of Northern China using an Idworx: https://picasaweb.google.com/100505759840318911139/2012China#5802971869831792898
...and the filthy pair of Maguras at the front: https://picasaweb.google.com/100505759840318911139/2012China#5802972089894777026

For the full slideshow of his wonderful journey, go to:
https://picasaweb.google.com/100505759840318911139/2012China#slideshow/5803113154593418418

All the best,

Dan.

[revelo]

I'm resurrecting this thread because I've since done some more touring and the scuffing/abrasion problem to the inner chain stays has not reoccurred. The initial tour was in Spring of 2012, and there was some mud at that time. I suspect it was the mud that caused the abrasion. This didn't occur to me initially because I was thinking that the rim brakes would have wiped all the mud off. But the rim brakes only touch the rim (duh..) and not the tires. So the mud (and grit inside the mud) that collected on the outsides of the tires would have been carried around and wiped against the chainstays and that is what caused the abrasion.

My subsequent tours were in dry weather. There was plenty of dust, but no mud. Upon inspecting the inner chainstays today, I noticed the touch-up paint I applied to those abraded areas after that initial tour is still mostly intact, though there are some scratch marks, perhaps from pebbles carried in the knobs on the sides of the tire.

Anyway, this clears up the mystery. I don't think this sort of abrasion can be avoided. My general feeling at this point, after 5000 miles and several months of touring on rugged dirt roads, is I don't really care if the frame or rear racks and other supposedly unlimited-lifetime components wear out eventually. Just buy replacements. Bicycles are cheap in the grand scheme of things, even expensive bikes like Thorn and expensive components like Rohloff. Certainly far cheaper than motor vehicles, houses, medical insurance and other big ticket items that some people buy but I am able to avoid buying.

[revelo]

I'm resurrecting this thread to reflect some new experiences that might be of interest to other people. My most recent tour was 80 days, 1929 miles in the Lassen National Forest of Northeast California, in the United States, from July to September 2013. Odometer is now at 7271 miles, or 11706 km. There were also some other tours since my previous update of this thread.

• Hebie chainglider failed to protect chain from dust, started to add drag as it became clogged with dust itself, and finally chainwheel began catching on the chainglider plastic, bending it out of shape and causing a rattling noise, which was annoying plus it might mask sounds of other bike components. So I threw the chainglider in the trash. This happened after exactly 3 weeks and 642 miles of riding on rugged dirt roads. Based on my experiences, I cannot recommend the Hebie chainglider for expedition touring.
  
• Thorn chain guard is an alternative for protection from getting pants dirty. However, now I've gotten my chain cleaning routine down pat, the chain is never really that dirty anymore, and thus getting my pants dirty is no longer a major concern, so I've decided not to get the chain guard at this point. (My pants are black, so I was only ever concerned about major amounts of grease, not trivial spots.)
  
• Chain cleaning routine no longer requires paper towels and also uses less chain cleaner. Dip a toothbrush in a 125ml Nalgene bottle filled citrus chain cleaner, wet down chain a little at a time while running it backwards, rinse chain using water bottle. Takes only about 15ml of chain cleaner, which means I only need to fill the Nalgene bottle every 8 cleanings. If I clean the chain once every week (about 200 miles), then I only need to refill the bottle once during a typical 2500 mile tour. A 900ml bottle of citrus chain cleaner costs only $3 at Walmart, in the auto parts department, versus about $10 for half that amount at the bike store. Of course, in either case I end up throwing most of the cleaner away, given that my Nalgene bottle is only 125ml. After cleaning and rinsing the chain, let it dry, then apply white lightening epic ride or similar silicone based lube to each link of the chain. The handles on toothbrushes nowadays are flimsy, so I carry a spare.
  
• When I returned from this tour, I measured the chain (which was new when I started the tour) and it had only stretched by .75%, which is the point at which conservative users are advised to replace their chains when using a derailleur system, though some people don't replace until the stretch is 1%. Because I'm running an internal gear hub, I could get by with a chain that had stretched way beyond 1%, but that would risk damaging the chainwheel and sprocket. So I replaced the chain with another SRAM PC830. So far there is very little wear on either chainwheel or sprocket. The chainwheel is new, since I replaced that after my last tour, but the sprocket is the same one that came with the bike originally.
  
• Difficulty turning eccentric to get new chain to fit, whereas it was easy to turn previously. Evidently, some of the Lassen dust has gotten inside the eccentric shell.
  
• Upon returning from the tour, I raised the saddle and handlebars by 2.4cm each and also modified the pedals to give better traction, to provide added power for ascending steep hills in the future. The pins I've been using on the Shimano PD-MX30 pedals were the short ones, so that my feet tended to slip unless I positioned the pedal under the middle of the foot. But that was causing me to lose much of my power. The reason I used these short pins was because the long ones cut deeply into my calves when I bumped them while pushing the bike during an early shakedown ride (see above in these notes), and I wanted to avoid that on tours. My plan now is to place a home-made pedal cover around the pedals to protect myself when pushing. Because I had lost the long PD-MX30 pins, I had to order new pedals. The PD-MX30 has been replaced by the PD-MX80, which is a much better design. The screws on the PD-MX80 are adjusted with a T15 torx wrench, and so won't get clogged by dirt like the tiny allen wrench hole in the PD-MX30 pins. Also, Shimano includes 8 spare screws and 16 spare spacers with the PD-MX80, whereas there were no spares with the PD-MX30, just one set of short pins and one set of long pins. I removed the spacers from 8 of the screws on each side of each of the new pedals, to provide maximum grip. The only screws which I did not adjust (and thus left at medium length) were those at the outside front corner of each side, since these are the screws most likely to hit my legs when pushing. I will carry the spacers and T15 torx wrench on my next tour, in case I decide the long screws cause problems.
  
• After about six weeks, I noticed my leg muscles were becoming unbalanced because I was only pedaling and never pushing. So I made a point from then on of pushing 2 miles (about 35 minutes) per day. During desert tours, there will probably always be sandy stretches where pushing is required, so I won't have to deliberately force myself to push on those tours.
  
• By the end of the tour, rear tire was showing some cracking in the sidewalls due to flexing, so I swapped with the front tire, which has no such cracks, presumably because it flexes less due to being less heavily weighted. Both tires have some nicks on the sidewalls from hitting sharp rocks, but the kelvar belts have prevented these nicks from penetrating deeply. And there is plenty of tread left. So I have little concern about using them for another 3000 mile or less tour. These Schwalbe Marathon Mondial 55-559 tires are great. The Schwalbe inner tubes are also great. I only had to add air twice during this trip. Ordinary tubes would have required weekly adjustment to keep the pressure up.
  
• I had no flats and didn't notice many goathead thorns during this tour, perhaps because I'm getting pretty good at recognizing goathead thorn areas and avoiding them. I'm going to experiment with tire liners on my next trip instead of putting sealant in the tubes, though I'll carry sealant in the repair kit. There was still some liquid sealant in the tubes. I've considered going tubeless, but that seems like a big hassle, though maybe not. I've never tried tubeless. Updated my webpage on this issue (see http://frankrevelo.com/hiking/biking_flatprevention.htm).
  
• Before performing the post-tour oil change, I first drained the existing oil, but very little came out. Evidently, the oil had mostly leaked out during the tour because of how I store the bike on its right side at night. I don't think this is a problem. I cleaned around the sprocket about halfway through the tour, and then it got oily again soon thereafter, so evidently there was still free oil in the hub at that point. Which means at most the hub was empty of oil for half the tour. But Rohloff says it is possible to run the hub for 5000km with no free oil, just whatever oil clings to the gears. So I'm probably okay.
  
• Rear rack is being abraded away by the bouncing of the panniers. There's been some discussion on this form of installing tape to stop this abrasion. I tried that but the tape only lasted a few days. Heavier tape might work, but then it would make the panniers hard to install and remove, which I do several times a day (install in morning, remove at lunch so I can access them while using the rest of the bike as a back rest, reinstall, remove again at end of day). Racks should last at least 7 years at my current rate of abrasion (about 500 hours of riding per year). Cost of new racks is about $150, including shipping. Divided by 7 that's $21/year. Trivial issue. Front racks show no abrasion, because I'm using home-made fabric panniers there.
  
• Checked spoke tensions with my Park TM-1 Spoke Tension Meter. All tensions at least 117kgf. Both wheels continue to be true and I did not tighten any spokes.
  
• No evidence of rim wear and brake pads showing minimal wear. These are the original pads that came with the bike.
  
• The Velox rim strips appear to have shifted on the rear rim somewhat, perhaps because of heat melting the glue as Andy Blance suggested might be a problem, but not enough to uncover any of the spoke holes. I'll keep a watch on this and perhaps switch back to the nylon rim strips at some point.
  
• At this point, my only suggestions for improving the bike would be: (a) wider handlebars for persons taller than me (I'm 180cm); (b) possibly allow Velox cotton rim strips rather than nylon rim strips as an option (though maybe not, based on how these Velox rim strips shifted since I installed them); (c) use 73x113mm rather than 73x110mm as the standard bottom bracket, whether or not user orders chain guard, to allow later retrofitting the chain guard without replacing the bottom bracket, given that the weight difference in these two bottom brackets is trivial; (d) make shifter cable housings identical lengths, so that spare shifter cables will be the same length, avoiding possible confusion during emergency repairs.
  

[JimK]

Thanks a zillion, Frank, for sharing all this experience! I dream of the sorts of adventures that you embark upon with remarkable regularity. Well, I got an overnight trip in this month, so I getting a wee bit beyond mere dreaming! But it is a great help in planning to learn from the experiences of others.